Two-dimensional active polar semiflexible polymer under shear flow.

The nonequilibrium structural and dynamical properties of semiflexible active polar polymers subject to linear flow are studied using numerical simulations. Filaments are confined in two dimensions and immersed in a fluid described by the Brownian multiparticle collision dynamics approach. The applied shear flow causes conformational changes in a polymer, aligns it along the flow direction, and induces a tumbling motion at high flow rates. In an intermediate, activity-dependent shear-rate regime, a characteristic scaling exponent for the mean-square end-to-end distance along the gradient direction is observed. This exponent appears to be determined by the semiflexibility of the polymer. The tumbling dynamics exhibits a characteristic time, with a stronger dependence on the Weissenberg number than that of flexible active or passive polymers. Activity strongly impacts the rheological properties of semiflexible polymers and even implies a negative viscosity for weak flows. At very large values of the shear rate, shear dominates over activity, and passive-polymer behavior is assumed.